Radiolytic Approach for Efficient, Selective and Catalyst-free CO 2 Conversion at Room Temperature.

The present study proposes a new approach for direct CO ₂ conversion using primary radicals from water irradiation. In order to ensure reduction of CO ₂ into CO ₂ ^-. by all the primary radiation-induced water radicals, we use formate ions to scavenge simultaneously the parent oxidizing radicals H ^. and OH ^. producing the same transient CO ₂ ^-. radicals. Conditions are optimized to obtain the highest conversion yield of CO ₂ . The goal is achieved under mild conditions of room temperature, neutral pH and 1 atm of CO ₂ pressure. All the available radicals are exploited for selectively converting CO ₂ into oxalate that is accompanied by H ₂ evolution. The mechanism presented accounts for the results and also sheds light on the data in the literature. The radiolytic approach is a mild and scalable route of direct CO ₂ capture at the source in industry and the products, oxalate salt and H ₂ , can be easily separated.
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